With development of display technology, flat display devices have become mainstream products in people's lives. Liquid crystal display (LCD for short) device is one of them. Taking a liquid crystal display device as an example, it includes a color filter substrate and an array substrate. During manufacturing the color filter substrate or the array substrate, a layer of film is formed on a base, and then a patterning process is performed on the layer of film, so as to form a predetermined pattern; subsequently, another layer of film is formed on the predetermined pattern, so as to form another layer of pattern. Above steps are repeated until the color filter substrate or the array substrate is formed.
Currently, base of the color filter substrate or array substrate is generally made of glass material. When transporting the base in production line, it is likely to be damaged due to various reasons. There are generally two damaged conditions, one is film damage (i.e., only the film on the base has been damaged), and the other is base damage (i.e., not only the film on the base has been damaged, the glass base itself has also been damaged). For different damaged conditions, different solutions have been employed, for example, the substrate with damaged film is reworked, so as to reuse the glass base, and however, when the glass base itself has been damaged, the damaged glass base has to be rejected immediately, as subsequent important apparatuses having high precision and high cost (e.g., coating machine and exposing machine) may be contaminated by glass fragments produced by the damaged glass base due to vibration of the production line.
Currently, a widely used method to distinguish film damage and base damage is as follows: as shown in FIG. 1, irradiating a substrate within a macro detection machine by an intense light source, and observing and determining damaged condition of the substrate by human eyes. By employing this method, apparent film damage (slightly damaged condition) and apparent base damage (severely damaged condition) can be distinguished. However, when damaged condition is moderate, it is hardly to be distinguished, by human eyes, whether the damaged condition is the film damage or the base damage, so that it is likely to make a wrong judgement. As a result, glass fragments are produced by the substrate judged as a substrate having film damage, the base of which has been damaged, in the subsequent processes, which will lead to a serious problem of the production line.
Thus, designing a detection device and a detection method for accurately detecting damaged condition of a substrate has become a technical problem to be solved urgently.
Herein, “damaged condition” refers to depth of damage from film side of a substrate to be detected.